Remove unnecessary List creation

pkg/analysis_server/lib/src/services/generated/completion.dart

Index: pkg/analysis_server/lib/src/services/generated/completion.dart
diff --git a/pkg/analysis_server/lib/src/services/generated/completion.dart b/pkg/analysis_server/lib/src/services/generated/completion.dart
index bad6d0d57298b5ec0e22255646cb5e95d40a6cfb..166f56baa237a4767ed6273a0a6e5039f4757e31 100644
--- a/pkg/analysis_server/lib/src/services/generated/completion.dart
+++ b/pkg/analysis_server/lib/src/services/generated/completion.dart
@@ -818,7 +818,7 @@ class CompletionEngine {
   bool _filterDisallows2(String name) => !_filter._match2(name);
 
   List<Element> _findAllNotTypes(List<Element> elements) {
-    elements = [];
+    List<Element> elements = <Element>[];

[sra1, 2014/10/26 06:31:39]

This local is shadowing the parameter.
The original code was using a new list instead of passing in a list.

Both are suspicious - the parameter has no purpose, and the function always
returns a new empty growable list.
Is there a unit test that would catch this?

The code should probably be using 
  elements.removeWhere((e) => ...);
  return elements;
to mutate the input, or
  return elements.where((e) => ...).toList();
to return a new list with some elements filtered out.

If the code should be mutating, I would make the return type void and use a
cascade at the call site, like the 'sort' example in another comment. 

[Brian Wilkerson, 2014/10/26 15:15:46]

Good catch! The original Java code was mistranslated. The original makes a copy,
so I used 'where'.

I'll work with Dan and Konstantin to figure out how best to test this.

     for (JavaIterator<Element> I = new JavaIterator(elements); I.hasNext;) {
       Element element = I.next();
       ElementKind kind = element.kind;
@@ -827,7 +827,7 @@ class CompletionEngine {
       }
       I.remove();
     }
-    return new List.from(elements);
+    return elements;
   }
 
   List<Element> _findAllPrefixes() {
@@ -841,7 +841,7 @@ class CompletionEngine {
   }
 
   List<Element> _findAllTypes2(List<Element> elements) {
-    elements = [];
+    List<Element> elements = <Element>[];

[sra1, 2014/10/26 06:31:39]

ditto

[Brian Wilkerson, 2014/10/26 15:15:46]

Same problem, same solution.

     for (JavaIterator<Element> I = new JavaIterator(elements); I.hasNext;) {
       Element element = I.next();
       ElementKind kind = element.kind;
@@ -850,7 +850,7 @@ class CompletionEngine {
       }
       I.remove();
     }
-    return new List.from(elements);
+    return elements;
   }
 
   List<Element> _findTopLevelElements(LibraryElement library, TopLevelNamesKind topKind) {
@@ -940,7 +940,7 @@ class CompletionEngine {
 
   List<ImportElement> _importsWithName(SimpleIdentifier libName) {
     String name = libName.name;
-    List<ImportElement> imports = [];
+    List<ImportElement> imports = <ImportElement>[];
     for (ImportElement imp in currentLibrary.imports) {
       PrefixElement prefix = imp.prefix;
       if (prefix != null) {
@@ -950,7 +950,7 @@ class CompletionEngine {
         }
       }
     }
-    return new List.from(imports);
+    return imports;
   }
 
   bool _isCompletingKeyword(Token keyword) {
@@ -1328,8 +1328,8 @@ class CompletionEngine {
         types.add(param.type.toString());
       }
     }
-    prop.setParameterNames(new List.from(params));
-    prop.setParameterTypes(new List.from(types));
+    prop.setParameterNames(params);
+    prop.setParameterTypes(types);
     prop.setParameterStyle(posCount, named, positional);
   }